Officers' volunteering for Crisis Intervention Team (CIT) training—rather than being assigned—is assumed to be an important, beneficial self‐selection bias. This bias remains poorly characterized, though CIT officers are more likely to be female and to have had exposure to the mental health field. We determined whether or not self‐selection is beneficial with regard to knowledge, attitudes, and skills, as well as level of force used (i.e., no or low force versus any form of physical force) and disposition of subjects, in actual encounters. We compared CIT‐trained officers who had volunteered with those who had been assigned using data from two prior, linked studies that compared CIT‐trained and non‐CIT officers on knowledge, attitudes, and skills (251 CIT‐trained officers; 68% had volunteered), as well as behaviors (517 actual encounters provided by 91 CIT‐trained officers; 70% had volunteered). Of 28 scores on knowledge, attitudes, and skills compared, six were statistically significantly different (p < .01) and another eight were marginally significant (.01 < p < .05). Furthermore, although CIT officers who had volunteered were more likely to report use of some form of physical force as we had defined it (which included the use of handcuffs), when they did so they were more likely to refer to treatment services and less likely to make an arrest. These effects were apparent even when taking into account effects of gender, having had exposure to the mental health field, empathy, and other covariates. In conclusion, we found evidence for benefits of self‐selection/volunteering that should be further characterized, as it appears to be associated with better outcomes with regard to key attitudes, skills, and behaviors.